title: Chemically triggered C-ON bond homolysis in alkoxyamines: regioselectivity and chemoselectivity.
abstract: Recently, we examplified the activation of the C-ON bond homolysis by protonation, alkylation, benzylation, acylation, oxidation and complexation with a Lewis acid of the nitrogen atom of the 1-(pyridin-4-yl)ethyl fragment (Chem. Commun., 2011, 4291 and Org. Lett., 2012, 358) and of the 1-(pyridin-2-yl)ethyl fragment (J. Org. Chem. ASAP Doi:10.1021/jo401674v) of (N-(2-methylpropyl)-N-(1-diethylphosphono-2,2-dimethylpropyl)-N-oxyl) SG1-based alkoxyamines. The quaternization of the 1-(pyridin-3-yl)ethyl fragment by the aforementioned reactions was investigated for the corresponding SG1-based alkoxyamines. In sharp contrast to the quaternization at ortho and para positions of the pyridyl moiety, the effect of the quaternization at the meta position was weak. The effects of quaternization at ortho, meta and para positions were investigated through natural bond orbital and Mulliken charges, HOMO-LUMO interactions in the starting materials and the radical stabilization energy of the released 1-puridylmethyl radicals using DFT calculations with the B3LYP/6-31G(d) and UBMK/6-311+G(3df,2p)//R(O)B3LYP/6-31G(d) methods, respectively.
authors.affiliation: Aix-Marseille Université, CNRS, ICR UMR 7273, case 551, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France. sylvain.marque@univ-amu.fr g.audran@univ-amu.fr paul.brémond@univ-amu.fr.
authors.forename: Gérard
authors.initials: G
authors.lastname: Audran
authors.forename: Paul
authors.initials: P
authors.lastname: Brémond
authors.forename: Matisse Bim Batsiandzy
authors.initials: MB
authors.lastname: Ibanou
authors.forename: Sylvain R A
authors.initials: SR
authors.lastname: Marque
authors.forename: Valérie
authors.initials: V
authors.lastname: Roubaud
authors.forename: Didier
authors.initials: D
authors.lastname: Siri